Snap-switch for electrical heating apparatus



W. R. SAVAGE.

SNAP SWITCH FOR ELECTRICAL HEATING APPARATUS. APPLICATION FILED-OCT. I2, I916.

Patented Oct. 12, 1920.

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If WW1 V A R s Suva-midi.

-w. R. SAVAGE.

SNAP SWITCH FOR ELECTRICAL HEATING APPARATUS.

APPLICATION FILED OCT. 12,1916.

Patented Jet. 12, 1920.

2 SHEETSSHEET 2.

WITNESS: Wi I I R. S a va g e INVENTOR.

UNI ED STATES PATENT OFFICE.

' WILL R. SAVAGE, 0F OMAHA, NEBRASKA.

SNAP-SWITCH FOR ELECTRICAL HEATING APPARATUS.

Specification'of Letters Patent. Patented Oct, 12, 192() Application filed October 12, 1916. Serial No. 125,332.

invention relates to controlling means for electrical heating apparatus, and particularly to snap-switches movable manually to positions for connecting two coils or heating elements either in parallel or in series, or for connecting only one of the coils with the supply circuit, or for disconnecting the coils from the supply-circuit. It is the object of my invention-to provide a compact and durable snapswitch for the above pur poses, having means by which, in passing from high to medium and low positions, a connection is constantly maintained between the moving blades of the switch and certain of the stationary contact-points so that not more than half of the maximum current transmitted to the heating coils is interrupted at any single point or by any single operation of the switch, thus adapting the same for use with apparatus requiring relatively large amounts of current for its operation, and reducing'to a minimum arcing and burning of the contacts. A further object of my invention is to provide accessory or auxiliary clrcultcontrolling means, operable coordinately with the heating-circuit controlling means,

for opening a thermostat-circuit and establishing a control-circuit for an automatic main switch, when the snap-switch is in off position.

In the accompanying drawings Figure 1 is a plan view of a switch embodying my invention, the cover, indicator-plate and operating-knob being removed, Fig. 2 is partial side-elevation and partial transverse section of the switch on the plane of the line 2-2 of Fig. 1, Fig. 3 is a partial bottom view showing the accessory circuit-controller, Fig. 4c is a detail side view of the rotary blade-carrier and stop-plate, and a part of the center-post, Fig. l is a detail plan view of the same and the ratchet-plate or stop-cam, Fig. 5 is a detail side view of one of the terminal-plates carrying the stationary contact-points, Fig. 6 is a detail side view of the center-post in. disassembled relation to certain parts which are mounted thereon in the completed structure, Fig. 7

is a detail plan view of the upper switchblades, Fig. 8 is a similar view of the lower switch-blades, Fig. 9 is a detail plan view of the indicator-plate and a part of .the cover, Figs. 10 and 11 are detail bottom views showing the accessory circuit-controller in two positions.

In the illustrated embodiment of my in-' vention, I provide a main body or base 20' stantially cylindrical in form and cylindri cally recessed at both its upper and lower ends. At the center of the body 20 a metal bushing 21 is fixedly secured therein, said bushing having an axial aperture in which the center-post 22 fits revolubly. To the upper end of the bushing 21 there is fixedly secured a plate 23 of which the form is subtantially that of a four-tooth ratchet-wheel,

and of which the teeth form stops for the snap-mechanism. A small eccentric 24 fits lnto notches in the sides of the center-post,

so as to be fixedly connected therewith and held in position just above the ratchet-plate 23. The eccentric fits revolnbly within thecentral aperture .of an annular plate 25 having a laterally extending finger with a downwardlyturned terminal portion 26 adapted for engagement with the teeth of the ratchetplate. The blade-carrier 27 fits revolubly upon the portion of thecenter-post above end of the oenter-post the same has a squared portion 29; and fitting upon said squared portion is a sleeve 30 having at its upper end a toothed flange 31. The sleeve is retained upon the squared portion of the post by means of a nut 32 screwed upon the threaded upper end portion :33 thereof. On said portion 33 there is also screwed the operating-knob 34, as shown in Fig. 2, and said knob serves to retain the cup-shaped metal .cover 35 in position upon the base. A helical spring 36 is disposed around the sleeve 30, the upper endof the spring engaging the toothed fiange 31 and the lower end of the spring being connected with the blade-carrier 27. The snap-mechanism, formed by the above described devices, is substantially identical with that of an ordinary and well-known type of snap-switch, and it will be understood that any suitable and the movement of the sleeve increases thetension of the spring 36. As the eccentric is rotated, from the normal position thereof indicated in Fig. 4, it moves the lateral finger of the stop-plate out radially until, after about a quarter-turn of the centerpost, the lug 26 slips off the end of the ratchet-tooth enga ed thereby and releases the stop-plate and lade-carrier. The latter are then rapidly advanced a quarter-turn by the spring 36, the lug 26 engaging the next tooth of the ratchet-plate and stopping the movement until the center-post and eccentric are turned enough farther to again release the lug 26 from the ratchet-tooth.

For indicating the various positions of the snap-mechanism, there is an indicatorplate 37 having a rectangular central aperture which fits upon the squared portion of the nut 32, the plate being thereby held in fixed relation to the center-post beneath the top of the cover 35. On the upper surface of the plate 37, near the outer edge thereof, are the marks Off, Hgh, Med and Low which are so spaced as to register successively With an aperture in the cover 35, as shown in Fig. 9, as the snap-mechanism is turned to the four stopping positions thereof.

The blade-carrier 27 has at opposite sides thereof two vertically extending posts 38, each of which is provided with a plurality of insulating bushings 39, between which the pairs of switch-blades 40 and 41 are held so that each pair of the blades is insulated from the posts. Each of the switch-blades has a central annular portion which is disposed concentrically with the center-post 22, and which has at opposite sides thereof apertures through which the posts 38 and portions of the bushings 39 extend. The lower pair of blades 40 have outer arcuate sectors of which the peripheral extent is slightly greater than a half-circle, and the upper pair of blades 41 have outer sectors of which the extent peripherally is less than a quadrant. The relation of the upper pair of blades to the lower pair is such that when viewed from above, as in Fig. 1, the forward ends of the outer sectors of the upper blades overlap the rearward ends of the lower blades by an amount substantially as indicated in said Fig. 1, wherein the rear end of the lower blades is shown by a dotted line.

On the upper side of the base 20, within the cover 35 and adjacent to the outer portions of the switch-blades, there are secured two pairs of terminal-plates 42 having binding-screws 43 for connecting the plates with wires extended up through openings 44 from the lower end of the base 20. The terminal-plates of each pair are sufficiently spaced from each other, to afford suitable insulation thereof and the pairs of plates are at substantially opposite sides of the base but slightly unsymmetrical to a vertical plane extending through the axis ofthe center-post. Three of said terminal-plates 42 have connected therewith contact-plates or points 45, 46 and'47, which extend inwardly therefrom in a horizontal plane lying between the lower pair of switch-blades 40, and said blades are so spaced vertically that when in appropriate positions their adjacent surfaces will engage and form an electrical connection with the upper and lower surfaces of said contact-plates. On two of the terminal-plates 42 there are Secured contact-plates or points 48 and 49 which extend inwardly therefrom in a horizontal plane such that they are similarly ary contact-points, with reference to the indicater-plate 37 and casing or cover 35,-is such that when the mark Off of the indicator-plate is shown through the aperture of the cover the lower switch-blades 40 engage only the contact-point 47, while the upper switch-blades 41 are not in engagement with the points 48 and 49 but are in position to engage said points at the next movement of the snap-mechanism; This Off position of the parts is indicated diagrammatically in Fig. 12. At the next po-' .sition on the mark Hgh of the indicator- 7 I The general arrangement of the switch-blades and station-v plate is exposed through'the cover, the up- 7 per blades 41 engage the contact-points 48 and 49, and the lower blades 40 engage the points 45 and 46, as indicated diagrammatically in Fig. 13. At the next position the mark Med is shownby the indicatorplate, the lower blades 40 remain or continue in engagement with the points 45 and 46, but the upper blades 41 pass out of engagement with the points 48 and 49, the positions of the parts being as representedin Fig. 1 and diagrammatically in Fig. 14. Atthe fourth position of the switch the indicator-plate shows the mark Low, the

' are again in the Off connection with electric lower blades 40 continue in engagement with the contact-point 46, passing out of engagement with the point 45 and passing into en' gagement with the point 47, and this relation of the parts is represented in Fig. 15. When advanced from the Low position the parts position first described.

The lower end of the center-post 22 pro jects through the bushing 21 into the cylindrical recess in the lower end of the insulating base 20, and on said portion of the post a cam 50 is secured by means of a nut 51 screwed on the threaded terminal portion of the post. as shown in Fig. 2, so as not to be in elec trical connection with the post. An arm 52 has one end thereof pivotally connected with the base by means of a screw 53, and the opposite end of said arm is movable between two terminal-plates 54 and 55 which are secured to the base and have suitable binding:

screws for the attachment of wires thereto. The arm 52 also has a binding-screw 56 near the pivoted end thereof. The central portion of the arm is annular in form and surrounds the center-post and the lower end of the bushing 21, the aperture in the annular arm-portion being large enough to permit movement of the arm between the plates 54 and 55 without engaging the bush ing. A small coil spring 57 has one end thereof connected with the pivoted arm and the other end connected with a pin 58 on the base, and said spring holds the arm normally in contact with the plate 54. At one side of the arm is a lug to which is secured a flat spring 59, the end of said spring extending into proximity to the cam 50 so as to be engageable thereby during a art of the rotation of the center-post 22. he cam 50 is 'so arranged, with respect to the upper portion of the switch mechanism, that when the latter is turned to the Oil position said cam will engage the spring 59 and move the pivoted arm into engagement with the terminal-plate 55, the spring 59 yielding to accommodate a slight excess movement of the cam after the arm engages the plate. At the other three positions of the switch mechanism the cam 50 is not engaged with the spring 59 and the arm is held, by the spring 57, in engagement with the terminal-plate 54.

The above described switch mechanism is intended and especially adapted for use in shown in my application Serial No. 785,970, filed August 21, 1913, which has resulted in Patent No. 1,267,700, issued May 28, 1918, having a double or compound heating element or coils such as shown in my application Serial No. 20,561, filed April 10, 1915, which has resulted in Patent No. 1,330,904, issued Feb. 17, 1920, and having an au- The cam is suitably insulated,

, and after movement than, the space contacts and adapted to extend from auxiliary contact of one pair to one o radiators such as center-post, a rotary blade-carrier mounted "'5 thereon, snap mechanism connecting said center-post and blade-carrier for intermittently actuating the latter to a series of positions, two pairs of switch-blades mounted on said carrier at positions spaced apart longitudinally of the center-post disposed in overlapping relation at one end and in V spaced relation at the other end, a pair of adjacent contacts engageable by one pair of the switcl blades at one position of the carrier, a second pair of contacts arranged substantially opposite the first pair and engageable by the second pair of switch-blades coincidently withthe engagement of the first pairs of blades and contacts, and a single contact connected with one of the first pair of contacts and engageable by the second pair of switch-blades, the latter switchblades being adapted to remain in engagementwiththe second pair of contacts during of the carrier to disengage the first pairs of blades and contacts, and said blades also being adapted to remain in engagement with one of said second pair of contacts during and after movement of the carrier to engage said blades with the single contac 2. An electrical snap switch including spaced pairs of fixed contacts located in dif ferent horizontal planes, one of the members of one pair of contacts having an auxiliary contact located in substantially the plane of the other pair, and a rotary blade carrier provided with upper and lower blades having arcuate portions of unequal length arranged in overlapping relation at one en and in spaced relation at the other end and engageable with the fixed contacts, the longer arcuate portion being of a length greater between the pairs of fixed the f the contacts of the other pair. I

3. An electrical snap switch including spaced pairs of fixed contacts located in different planes, one of the members of one of the pairs of contacts having an auxiliary contact arranged in substantially the plane of the other pair of contacts, and a rotary blade carrier provided with blades having arcuate portions of unequal length arranged in overlapping relation at one end and in spaced relation arcuate portion being movable into and out of contact with one of the pairs of contacts at the other end, the shorter and the other arcua te portion being movable into and out of contact with the other pair of contacts and into engagement with one of the same and the auxillary contact and also in engagement with only the auxiliary contact.

4. An electrical snap switch including spaced pairs of fixed contacts and a rotary blade carrier having blades provided with arcuate portions of unequal length arranged in overlapping relation at one end and in spaced relation at the other end, the shorter arcuate portion being movable into and out of engagement with. one pair of contacts and the longer arcuate portion being arranged to engage the other pair of contacts and being of a length to remain in engagement withithe same during and after the movement of the carrier to disengage the shorter arcuate portion from the other set of contacts.

5. An electrical snap switch including spaced pairs of fixed contacts, one of the members of one pair of contacts having an auxiliary contact, and a rotary blade carrier having blades provided with arcuate portions of unequal length arranged in overlapping relation at one end and in spaced relation at the other end, .the shorter ar'cuate portion being movable into and out of engagement with one pair of contacts and the longer arcuate portion being arranged to engage the other pair of contacts and being of a length to remain in engagement with the same during and after the movement of the carrier to disengage the shorter arcuate portion from the other set of contacts an d also to remain in engagement with its fixed pair of contacts until by further movement it is carried into engagement with the auxiliary contact so that the circuit with which such fixed contacts is connected will not be broken until the said longer blade engages one of them and the auxiliarylcontact.

WILL R. SAVAGE. 

